Numerical analysis of ablated behaviors on titanium irradiated by high-intensity pulsed ion beam

The axisymmetric model of heat transfer in materials irradiated by high-intensity pulsed ion beam (HIPIB) was constructed based on the temporal and spatial distribution of the HIPIB. The ablated behaviors on titanium irradiated by HIPIB during a pulse width of 120 ns with the shots up to 10 was investigated using the enthalpy formulation under an energy density range from 0.1 to 120 J/cm2, considering the HIPIB energy absorption coefficient of materials. At the first shot, the critical energy density for melting and ablating on the irradiated titanium was 0.2 and 0.7 J/cm2, respectively, and as the energy density increased up to 120 J/cm2, the onset times for melting and ablating were shorten and their interval was also decreased. After 2 shots, both the onset times were delayed and the time interval was increased, whereas following the shots up to 10, both the onset times were kept at constant. As the energy density increased from 0.7 to 120 J/cm2, the melting and ablating depths at the center of sample surface increased, the thickness of liquid layer in initial stage increased and then decreased after the first shot. During the pulse, both the melting and ablating depths increased monotonically, while the thickness of liquid layer initially increased, then decreased, and finally increased again. For the shots up to 10, both the depths increased with the constant thickness of liquid layer. The ablation mass of titanium irradiated by HIPIB with the shots up to 10 under an energy density from 0.7 to 120 J/cm2 was obtained from the calculated ablating depth. The calculated ablation mass of irradiated Ti sample with 10 shots under the energy density of 70 J/cm2 was consistent with that measured by HIPIB irradiation experiments.